1. Field of the Invention
The present invention relates to a reception performance measuring apparatus and, more particularly, to an apparatus for measuring reception performance of a TV (abbreviation for television) signal.
2. Description of the Background Art
Conventionally, a TV input signal is displayed in the form of an image on a screen via a tuner set by a CVBS (Composite Video Base-band Signal).
In measuring reception performance of TV signal by a tuner set, while changing conditions of each channel, appearance of noise on the screen is monitored by visual check for every condition being changed. As a result of such a monitoring, when noises do not appear within a prescribed period of time (for example, 20 msec), it is determined that the reception performance of the tuner set is right.
As described above, since conventional measurement of reception performance relied on manual measurement by an operator and hence entailed human errors, the efficiency was not satisfactory.
On the other hand, as a technique relating to measurement of reception of TV signal, an apparatus disclosed in Japanese Patent Laying-Open No. 2000-32365 is known. In this apparatus, a correction bit number outputted from an error rate detection circuit is inputted into a microcomputer control circuit, and divided by a reference bit number stored in the microcomputer control circuit by means of software, and then the result is outputted as an error rate signal.
Furthermore, Japanese Patent Laying-Open No. 2000-299665 discloses a technique of simultaneously measuring a reception level of electric wave and a bit error rate.
Furthermore, Japanese Patent Laying-Open No. 2002-94487 discloses a procedure of making a computer execute bit error measurement of transmission line.
The techniques disclosed in the above publications merely disclose measuring or detecting of bit error of digital data, and not suggest any techniques concerning measurement of reception performance of composite signal of TV signal.